Ultrasonic-assisted Method Research Articles

Effects of Copper Doping on Fluorohydroxyapatite Coating: Analysis of Microstructure, Biocompatibility, Corrosion Resistance, and Cell Adhesion Characteristics.

In this research, Cu-doped fluorohydroxyapatite (Cu-FHAp) coatings containing varying levels of Cu in electrolyte as a dopant were synthesized by the ultrasonic-assisted pulse-reverse electrodeposition method on AZ31 alloy to improve the biocompatibility and corrosion resistance of the alloy for biomedical applications. Microstructural analysis revealed that the inclusion of the Cu dopant results in the formation of a more uniform coating. Energy dispersive spectroscopy analysis highlights a notable incorporation of copper within the fluorohydroxyapatite structure. The increase in Cu content significantly affected surface roughness and elevated hydrophobicity, leading to a contact angle of up to 136°. Electrochemical impedance spectroscopy analysis revealed that all samples containing copper exhibited favorable corrosion resistance, with the sample prepared using the electrolyte containing 0.036 g/L Cu(NO3)2 demonstrating the highest corrosion resistance. Cell adhesion evaluation yielded a satisfactory cell adhesion to the coated samples, indicating that the presence of the optimum value of Cu does not induce considerable cytotoxic effects.

Evaluation of Annona muricata Linn Leaves Extracts from Maceration and Ultrasonic-Assisted Methods for Anticancer Activity on HLFa Cells

Non-small cell lung cancer (NSCLC) is a deadly kind of cancer that contributes significantly to the global cancer mortality rate. It is distinguished by a significant level of malignancy and unfavourable prognosis. The molecular pathways responsible for tumour invasion and migration in NSCLC are not fully understood, despite their widespread occurrence and significant consequences. Moreover, the ability of cancer cells to withstand the effects of chemical treatments presents a substantial obstacle in the creation of successful treatment approaches for NSCLC. Annona muricata Linn (A. muricata) is known to possess powerful anticancer bioactive components. A. muricata extracts have demonstrated significant therapeutic potential among a wide range of botanical compounds. However, the specific molecular interactions of the plant have not yet been revealed. This study aims to evaluate the anticancer potential of A. muricata leaves extracts on the NSCLC cell line and compare the efficacy of two different extraction methods, namely maceration extraction (ME) and ultrasonic-assisted extraction (UAE). Results showed that ME demonstrated significantly higher antioxidant activity compared to UAE, with respective percentages of 81.4% and 29.4%. However, the UAE extract demonstrated more pronounced cytotoxic effects on the NSCLC cell line (HLFa) with an IC50 value of 139.6 µg/ml, indicating a stronger antiproliferative effect on cancer cell. Both ME and UAE extracts reduced nitrite release in HLFa cell supernatants, with the ME extract showing superior activity. Treatment with ME and UAE also resulted in the activation of Caspase3/7, indicating the induction of apoptosis in HLFa cells compared to the untreated control. The extracts and Cisplatin differ approximately 0.3-fold in caspase 3/7 activation though it was not statistically significant. This activation suggests that both extraction methods effectively initiate the apoptotic cascade which is crucial for the elimination of cancer cells. Furthermore, the UAE extract significantly reduced BCL-2 mRNA levels (p<0.05). The significant reduction in BCL-2, a protein that prevents apoptosis reflect the extract’ ability to modulate key apoptotic regulators with the most significant activity when UAE extracts were used. In summary, A.muricata leaves extracts obtained through both ME and UAE methods exhibited promising anticancer effects against NSCLC, with UAE extracts exhibiting superior activity. These findings pave the way for further investigations into the use of A.muricata in cancer treatment and the development of new therapeutic agents based on its properties.

Preparation of artificial humic acid from corn straw and its high-efficiency adsorption on norfloxacin

In this study, the biomass artificial humic acid (AHA) with efficient adsorption performance for norfloxacin (NOR) was prepared by ultrasonic-assisted acid-alkaline combined hydrothermal method with corn straw as raw material. Characterization analysis showed that AHA was a typical amorphous structure, and the oxygen content of AHA prepared by ultrasonic-assisted hydrothermal method was obviously improved compared with that without ultrasonic-assisted method. The saturated adsorption capacity of AHA was 551.53 mg/g, which was higher than that of other reported materials, such high-efficiency adsorption is due to the abundant oxygen-containing groups (–OH, –C=O, etc.) in AHA, which were functional groups that can be π-π stacked, hydrogen bonded and electrostatically bonded with NOR. It had good selective adsorption for NOR, with less interference from acidity of environmental water, coexisting inorganic ions and common antibiotics. When it was applied to adsorb NOR with concentration of 10.0 mg/L in simulated water prepared by environmental water, the highest removal rate was 91%, which indicated that AHA could not only remove all the NOR in the polluted water with complex components at the highest concentration of 630 μg/L, but also its adsorption capacity far exceeded the pollution amount. The research had important practical significance in realizing the recycling of agricultural wastes and the removal of environmental pollution.

Cobalt vanadate intertwined in carboxylated multiple-walled carbon nanotubes for simultaneous electrochemical detection of ascorbic acid, dopamine and uric acid

Low-cost transition metal vanadate-based electrochemical sensors have attracted a lot of attention recently. A cobalt vanadate and carboxylated multi-walled carbon nanotube composite (CoV/MWCNTs-COOH) was prepared by an ultrasonic-assisted assembly method. The uniform and dense MWCNTs-COOH attached to the surface of CoV not only combines the large surface area and superior conductivity of MWCNTs-COOH with the excellent electrochemical activity of CoV, but also enhances the redox reaction between CoV/MWCNTs-COOH composite and the analyte through synergistic effect of hydrogen bonding and electrostatic interaction. The electrochemical behaviors of CoV/MWCNTs-COOH composite modified glassy carbon electrode (CoV/MWCNTs-COOH/GCE) were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The simultaneous electrochemical sensing of ascorbic acid (AA), dopamine (DA) and uric acid (UA) on CoV/MWCNTs-COOH/GCE possesses good peak current signals with well-defined peak potentials. The linear ranges of AA, DA, and UA at CoV/MWCNTs-COOH/GCE are 1.0–100.0 μM, and the limits of detection (LODs; S/N = 3) are 0.4 μM, 0.03 μM, and 0.1 μM, respectively. The practicality of the designed sensor was further confirmed by the good recoveries obtained in the simultaneous measurement of actual samples including fetal bovine serum, human serum, urine, and Vitamin C tablets. Overall, the developed electrochemical sensor shows potential therapeutic applications for simultaneous determination of AA, DA and UA in biological fluids.

Deciphering the structural origin for the remarkable CO oxidation activities of the CuO-based catalysts with diverse morphological CeO2 supports

In this work, octahedral, cubic, particle-like, spherical and rod-shaped nano-CeO2 supports were synthesized by hydrothermal method. CuO/CeO2 catalysts were then prepared via an ultrasonic-assisted impregnation method, employing these differently shaped CeO2 supports. The resulting catalysts were tested for their performance in CO oxidation. The findings revealed that the CuO active sites significantly influenced the oxygen storage and release capacity of CeO2, thereby improving its catalytic activity for low-temperature CO oxidation. The key factors affecting the CO oxidation performance of CuO/CeO2 catalysts with different CeO2 morphologies were investigated through various characterizations. It was found that the specific surface area was not the primary factor in determining catalytic activity. Instead, the exposed crystal planes played a crucial role. By adjusting the crystal plane exposure of CeO2, the supported 1CuO/CeO2 catalysts exhibited different crystal surface configurations. Notably, the 1CuO/CeO2-S catalyst, with exposed (100) and (110) crystal planes, and the 1CuO/CeO2-P catalyst, with exposed (111), (100), and (110) planes, exhibited higher surface defect concentrations. This increased defect concentration facilitated the formation of Cu+ species, enhancing the redox properties and further improving the overall catalytic performance of CO oxidation.

Deep eutectic solvent-based ultrasonic-assisted extraction of polyphenol from Chenopodium quinoa Willd.: Optimization and lipid-lowering activity

Hyperlipidemia poses a serious threat to human health, but its medication remains some issues including significant adverse reactions. Polyphenols exhibit great potential in lowering blood lipids and the lipid-lowering effects of quinoa polyphenols are still waiting to be explored. In this study, a deep eutectic solvent-based ultrasonic-assisted extraction method of quinoa polyphenols was developed. Then, the constituents of quinoa polyphenols after purification CQP were analyzed. Besides, their lipid-lowering activities and mechanism were explored. Results suggested that CQP comprised at least 12 kinds of polyphenols. CQP could inhibit lipase, adsorb cholesterol, inhibit oxidative stress and lipid peroxidation. Subsequent network pharmacology, cellular experiments and molecular docking revealed that CQP might influence the expression levels or bind to AKT1 and FOXO1, thereby affecting their content or activity, ultimately regulating their functions and leading to changes of the cellular lipid levels. This study lays foundation for developing novel lipid-lowering drugs and functional foods.

Unraveling the Ultrasonic-Assisted Synthesis of Green-Emitting CsPbBr3@Cs4PbBr6: Reaction Process, Luminescence Property, and Display Application.

The pursuit of stable and highly emissive perovskite materials has garnered increasing attention in optoelectronic applications. Green-emitting CsPbBr3@Cs4PbBr6, as a green-emissive material in the solid-state form, has great potential as a color conversion material for full-color displays. However, it is a challenge to achieve mass preparation under ambient conditions. Meanwhile, the formation mechanism is ambiguous. This study reports a ligand-free and rapid mass synthesis of nanomicrosized CsPbBr3@Cs4PbBr6 solid via an ultrasonic-assisted method. The synthesized CsPbBr3@Cs4PbBr6 solids exhibit uniform morphology, high stability, and solid-state quantum efficiency of approximately 55%. Moreover, the transformation mechanism from Pb-Br complexes in the synthesis process is fully investigated by monitoring the phase and spectral evolution. By employing it as a green emitter, the obtained white light-emitting diode (LED) device shows high performance with a correlation color temperature of 7635 K and a wide color gamut of 123% NTSC. This study offers a low-cost and simple operation mass production method for solid-state perovskite powders with excellent chemical stability. Additionally, it provides new insights into the formation mechanism of highly efficient perovskite materials and promotes their practical applications.

Research on ultrasonic-assisted vibration multi-cycle compaction method of flexible guided 3D weaving

The structure of three-dimensional (3D) preforms is the key to the performance of 3D reinforced composites. In order to improve the quality and efficiency of manufacturing, this paper originally proposes the ultrasonic vibration-assisted multi-cycle compaction method. Ultrasonic vibrations are applied, using a resonant 40 kHz compactor, to the compaction of 3D carbon fiber preform. Compared to the traditional method, the ultrasonic vibration-assisted multi-cycle compaction method can accelerate stress relaxation and reduce preform springback. The microstructure of preform is observed using x-ray computer tomography imaging. It elucidates the mechanism by which ultrasonic vibration promotes fiber slippage. The compaction forming experiment of preforms has proven that the ultrasonic vibration-assisted multi-cycle compaction method can reduce the compaction time, improving the forming quality. This can improve the technical support for the improvement of the manufacturing level of the 3D preform.

Recent Trends and Advancements in Green Synthesis of Biomass-Derived Carbon Dots

The push for sustainability in nanomaterials has catalyzed significant advancements in the green synthesis of carbon dots (CDs) from renewable resources. This review uniquely explores recent innovations, including the integration of hybrid techniques, such as micro-wave-assisted and ultrasonic-assisted hydrothermal methods, as well as photocatalytic synthesis. These combined approaches represent a breakthrough, offering rapid production, precise control over CD properties, and enhanced environmental sustainability. In addition, the review emphasizes the growing use of green solvents and bio-based reducing agents, which further reduce the environmental footprint of CD production. This work also addresses key challenges, such as consistently controlling CD properties—size, shape, and surface characteristics—across different synthesis processes. Advanced characterization techniques and process optimizations are highlighted as essential strategies to overcome these hurdles. Furthermore, this review pioneers the integration of circular economy principles into CD production, proposing novel strategies for sustainable material use and waste reduction. By exploring innovative precursor materials, refining doping and surface engineering techniques, and advocating for comprehensive life cycle assessments, this work sets a new direction for future research. The insights provided here represent a significant contribution to the field, paving the way for more sustainable, efficient, and scalable CD production with diverse applications in optoelectronics, sensing, and environmental remediation.

Synergistic effects of Fe2O3 supported on dendritic fibrous SBA-15 for superior photocatalytic degradation of methylene blue

Environmental pollution caused by dye effluent has attracted much attention, and thus developing photocatalysts with superior photodegradation performance is an imperative task. A series of Fe supported on dendritic fibrous SBA-15 (Fe/DFSBA-15) catalysts with various Fe contents were prepared using a microemulsion coupled with ultrasonic-assisted impregnation methods. The findings revealed that the structural stability of DFSBA-15 was unaffected by the amount of Fe loaded. As the Fe loading increased, the size of Fe2O3 nanocrystals increased while the catalysts’ surface area decreased. The bandgap energy of the catalyst decreased with increasing Fe loading and became constant after reaching an optimal Fe loading of 10 wt%. The one-factor-at-a-time study revealed that 10Fe/DFSBA-15 degraded 94.72 % of methylene blue (MB) within 180 min at 1.5 g/L catalyst dosage, pH 8, and 10 mg/L of concentration, owing to Si-O-Fe coordination, modest Fe2O3 crystallite size, homogeneous metal distribution, slower recombination rate, and low bandgap energy. The advantageous features of 10Fe/DFSBA-15 resulted in accelerating the photodegradation rate, where 10Fe/DFSBA-15 is found as the optimal catalyst. The addition of Fe particles to the DFSBA-15 largely improved their photocatalytic activity toward MB degradation, making it a potential candidate for removing pollutants from aqueous solutions.

CoMo/g-C3N4 as a highly effective, reusable, non-noble metal-based catalyst for H2 production via NaBH4 hydrolysis focused on stationary application under mild conditions: A kinetic study

Among hydrogen storage chemicals for proton exchange membrane fuel cells (PEMFCs), sodium borohydride stands out for yielding exceptionally pure hydrogen. This study synthesized cobalt-molybdenum catalysts supported on g-C3N4 using an ultrasonic-assisted impregnation method. Various CoMo/g-C3N4 catalysts with different CoMo mass ratios were created, all showing high hydrogen production and complete NaBH4 conversion under mild conditions. Catalytic activity depends on the cobalt-molybdenum mass ratio, with optimal performance at a 1:1 ratio (w/w), maintaining up to 83% activity over 5 cycles. The effect of operating conditions on hydrogen release was explored, resulting in the rate law: rH2 = 1.708 × 10-3 [NaBH4]1.25 [Catalyst dosage]1.39 [NaOH]0.44 at 298 K, with a low activation energy of 22.9 kJ mol−1. Molybdenum's promoting effect prevented significant deactivation of the cobalt catalyst, ensuring complete NaBH4 conversion to H2 and good stability over multiple cycles.

Comparative study of the sequential extraction methodologies for fractionation analysis of mercury in coal of Thar coalfield.

The primary objective of this study was to evaluate the bound fractions of mercury (Hg), physicochemical parameters, and mineral composition of coal. Coal samples were collected from various depths within Block-VII of the Thar coalfield in Pakistan. The Hg associated with different chemical fractions of coal was extracted using a sequential extraction scheme as per the community bureau of reference (BCR) protocol. This study utilized both the BCR-sequential extraction method (BCR-SEM) and a single-step sequential extraction based on an ultrasonic-assisted method (SSE-UAM) for the fractionation analysis of Hg in coal. The extraction methodologies, BCR-SEM and SSE-UAM, were specifically designed for analyzing Hg fractionation in coal samples. The SSE-UAM offers an operational advantage, requiring only 2h compared to the 51h needed for BCR-SEM. The analyses were validated using standard reference material (SRM-1635a) and the spiking addition method, achieving a recovery percentage of 97.1% for total Hg concentrations using the pseudo-extraction method in SRM-1635A. Total Hg content in the coal samples ranged from 0.60 to 2.34µgg-1 across four different coal seams from Block-VII of the Thar coalfield. Additionally, Hg concentration was observed to decrease with increasing depth, attributed to changes in mineralogical composition. The highest concentration of Hg was detected at a depth of 200-203m, while the lowest concentration was at a depth of 152-154m. The concentration of Hg in various fractions was 32-60% in the acid-soluble fraction, 1.72-4.92% in the reducible fraction, and 9.58-50.8% in the oxidizable fractions. The coal sample characteristics were analyzed using an elemental analyzer and scanning electron microscopy with energy-dispersive spectroscopy. Cold vapor atomic absorption spectrometry (CV-AAS) was used to measure the extracted fractional concentration of Hg in coal.

Facile synthesis of KV3O8 nanobelts for solid-state supercapacitors

Electrochemical supercapacitors emerge as promising energy storage systems for various electronic applications owing to their low cost, safe operation, and long lifespan. However, the limited choice of cathode materials and lack of green and scalable synthesis strategies largely hinder their practical applications. Herein, we describe a facile ultrasonic-assisted chemical method for synthesizing potassium vanadate (KV3O8) nanobelt as cathode material for asymmetric supercapacitor application. It demonstrates excellent electrochemical performance in terms of high-rate capability, specific capacitance, operating voltage (1.8 V), and energy density (51 Wh kg−1). This work provides a new strategy for fabricating high-performance electrode material using a simple and low-cost ultrasonic-assisted chemical method which is highly efficient and suitable for large-scale production to develop advanced energy storage devices. By addressing the key challenges in the field, this study contributes to the advancement of sustainable and efficient energy storage solutions.

Ultrasonic assisted synthesis of nanoporous carbon/CeVO4 nanocomposite for supercapacitor and photocatalytic applications

Here, nanoporous carbon (NPC)/CeVO4 nanocomposite synthesized via ultrasonic assisted method for supercapacitor and tartrazine dye degradation application. Transmission electron microscope (TEM) studies confirmed the CeVO4 nanoparticles well embedded on the NPC surface in the NPC/CeVO4 nanocomposite. Spherical shaped CeVO4 nanoparticles are well incorporated on the surface of NPC therefore NPC/CeVO4 nanocomposite which possess a porous-like structure would improve the supercapacitor applications and dye degradation performance. As expected, the specific capacitance (Cs) values (555 F g−1) of NPC/CeVO4 nanocomposite showed enhanced performance as compared to CeVO4 nanoparticles (234 F g−1) at a current density of 1 A g−1 and the capacitance retention of the designed electrode as 95 % after 5000 cycles. The photodegradation of tartrazine dye using pure CeVO4 nanoparticles and NPC/CeVO4 nanocomposite was explored under visible light irradiation. The photocatalytic degradation experiment demonstrated that the NPC/CeVO4 exhibits the maximum degradation efficiency (98.76 %) of the tartrazine with was reached within 120 min. Moreover, the rate constant of NPC/CeVO4 for tartrazine dyes decomposition was 0.0192 min−1 representing that it is two-fold higher than pure CeVO4 (0.0073 min−1). The superior electrochemical and photocatalytic properties of NPC/CeVO4 nanocomposite have been observed due to the well-designed structure and high surface area. Consequently, as-prepared NPC/CeVO4 material could be a promising material for electrochemical supercapacitor and dye degradation of the tartrazine organic pollutant.

A comparative study of the Au/n-Si (MS) and Au/(ZnO:CeO2:PVP)/n-Si (MPS) Schottky structures by using current/voltage characteristics in dark and under illumination

In the present study, both metal/semiconductor (MS) and metal/polymer/semiconductor (MPS) Schottky Diodes (SDs) were grown onto the same n-Si wafer to compare their electrical and optical characteristics. Firstly, ZnO and CeO2 nanostructures were synthesized by ultrasonic-assisted method (UAM), and structurally characterized by utilizing x-ray diffraction (XRD), Ultraviolet-visible spectroscopy (UV–vis), and Fourier-Transform-IR (FTIR) methods. The mean submicron crystallite sizes were estimated to be below 11.39 nm for CeO2 and 54.37 nm for ZnO nanostructures through the Debye–Scherrer method. The optical bandgap was calculated as 3.84 eV for CeO2 and 3.88 eV for ZnO nanostructures via Tauc plot. Electrical parameters such as reverse-saturation current (Io), ideality-factor (n), zero-bias barrier height (ΦBo), and rectification-ratio (RR) were found as 0.596 μA, 5.45, 0.64 eV, 2.74 × 105 in dark and 5.54 μA, 5.88, 0.59 eV, 8.60 × 103 under illumination for the MS SD and 0.027 μA, 4.36, 0.72 eV, 1.85 × 107 in dark and 0.714 μA, 5.18, 0.64 eV, 7.61 × 104 under illumination for the MPS SD, respectively. The energy-dependent profile of surface-states was obtained via the Card-Rhoderick method, by considering ΦB(V) and n. RR of the MPS SD is almost sixty-seven times the RR of the MS SD in the dark. The sensitivity of the MPS SD (=710) is nineteen and five-tenths the sensitivity of the MS SD (=36.4), so the MPS SD is considerably more sensitive to illumination. These results indicate that the (ZnO:CeO2:PVP) organic interlayer significantly improves the performance of the MS SD.

Multifunctional Characterization and Anticancer Properties of Magnetic Zinc Ferrite Nanoparticles by Modified Ultrasonic Assisted Co-precipitation Method

Zinc Ferrite (ZnFe2O4) nanoparticles were synthesized successfully via the modified ultrasonic-assisted co-precipitation method. Structural characterization, conducted through X-ray diffraction (XRD) analysis and Rietveld refinement, revealed a single cubic phase with a mixed spinel structure. Fourier transform infrared spectroscopy confirmed the presence of functional groups indicative of the spinel ferrite structure. Morphological analysis using field-emission scanning electron microscopy showcased the nanoparticles’ uniform morphology and size distribution. UV–vis spectra revealed the optical properties, while the Tauc Plot method determined the optical band gap. Electron paramagnetic resonance spectra confirm the symmetric resonance peak with 1254 Oe line width and the Lande g value 2.133. Magnetic hysteresis loops confirm the soft magnetic nature of the nanoparticles with magnetic saturation and coercivity of 39.2 emu gm−1 and 77.5 Oe. The anticancer properties against various cancer cell lines (HeLa, HepG-2 and MCF-7) revealed significant anticancer activity against HepG-2 and HeLa cells compared to MCF-7 cancer cells, and the results were compared with the standard drug cisplatin. A comparative analysis of results among cancer cell lines was conducted and discussed.

Promisingly prioritized elimination performance of europium and uranium from industrial wastewater by recyclable polydopamine functionalized hydroxyapatite/ZIF-67 hybrids

In recent decades, the nuclear industry has undergone robust growth leading to an increasingly severe issues of radionuclide contaminants in wastewater. Consequently, the development of a novel, efficient, regenerative and environmentally friendly adsorbent has become a significant challenge. In this study, recyclable polydopamine functionalized hydroxyapatite/ZIF-67 (HAP/ZIF-67/PDA) hybrids with a mass of functional groups, were successfully synthesized using the ultrasonic-assisted method. The especially characterized techniques illustrated that the HAP/ZIF-67/PDA hybrids were outstanding stable, excellent physicochemical properties and abundant functional groups. The elimination performances of Eu(III) and U(VI) from wastewater were also explored and deliberated through macroscopic experiment under diverse wastewater chemistry environment. The optimal adsorption capacity of HAP/ZIF-67/PDA was approximately 1.33 × 10-3 mol/g for Eu(III) and 8.85 × 10-4 mol/g for U(VI), surpassing those reported materials in previous literatures. The particular adsorption isotherms of Eu(III) and U(VI) were favorably fitted by Langmuir model, illustrating that the adsorption Eu(III) and U(VI) were totally endothermic reaction. The remarkable adsorption performance of HAP/ZIF-67/PDA hybrids (within 80 min for Eu(III) and 100 min for U(VI)) was verified through dynamic model, and then the kinetics results were well simulated through pseudo-second-order kinetic model, which further illustrated outstanding performance for rapidly treating Eu(III) and U(VI) under extreme emergency conditions. The primary adsorption mechanisms HAP/ZIF-67/PDA hybrids towards Eu(III) and U(VI) were surface complexation, competitive interaction, cation change, π-π* bonds and electrostatic interaction. Based on the excellent adsorption performance and recyclability of HAP/ZIF-67/PDA, it holds significantly potential and promising prospects for the efficient elimination of lanthanide and actinium contaminants from the practical treatments and disposals fields of industrial wastewater.

Study on ultrasonic-assisted machining methods and surface topography of C/C composite thin-walled small holes

Study on ultrasonic-assisted machining methods and surface topography of C/C composite thin-walled small holes

Utilization of Butterfly Pea Flower as Shelf-Life Colour Indicator for Keropok Lekor Smart Packaging

Studying the feasibility of using Clitoria ternatea or butterfly pea extract (BPE) as a colorimetric indicator to determine the shelf life of Keropok Lekor would aid in monitoring storage conditions, emphasizing its potential contribution to the smart packaging industry. The objective of this research is to develop pH-sensitive packaging using gelatine film infused with butterfly pea extract (BPE) along with ultrasonic-assisted extraction methods. The investigation involves quantifying the physicochemical attributes of the extracted butterfly pea and ascertaining the colour alterations during the storage of Keropok Lekor over a duration of six days. The determination of total anthocyanin content in BPE, conducted through a pH differential assay, yielded a value of 1.08 mg/g. Texture analysis revealed that the film with 10% BPE exhibited elevated tensile strength (0.11±0.01) and toughness (0.03±0.01). Total phenolic compound analysis indicated that the film containing 30% BPE possessed the highest value at 0.16±0.02. Notably, the film with 30% BPE demonstrated the highest colour change in Keropok Lekor storage from dark blue (-22.5±80.95) to dark green (6.34±1.85) over the course of six days. The film incorporated with 30% BPE stands as a viable colour indicator, demonstrating the potential for monitoring the freshness and quality of Keropok Lekor.

Zinc Oxide/Polypyrrole particle-decorated rod structure for NO2 detection at low temperature

In this study, Zinc oxide (ZnO) nanoparticles with a size of about 50 - 70 nm were green-synthesized using tea leaves and ZnO/Polypyrrole (ZnO/Ppy) nanocomposites were obtained by ultrasonic-assisted chemical polymerization method using pyrrole monomer and the nanoparticles. The characterization of the materials is conducted using several analytical techniques, including Field Emission Scanning Electron Microscopy (FESEM) and X-Ray Diffraction (XRD) and Ultraviolet visible spectrum (UV-Vis). The synthesized PPy material exhibits have a rod-shaped structure, diameter ranging from 100 to 200 nm. The ZnO/PPy nanocomposite system, consisting of PPy rods surrounded by ZnO particles. The gas sensing characteristics of the materials have also been investigated by measuring their sensitivity, response time, and stability to NO2 at low temperature and different humidity. Notably, the material exhibits considerable sensitivity to NO2 gas at low temperatures and the parameters related to response and recovery times are relatively rapid. Furthermore, a potential gas-sensing mechanism based on changes in the width of the depletion region is proposed.